1. Field of the Invention
The present invention relates to an electric-component supplying method and apparatus and particularly to the art of improving the efficiency of supplying of electric components.
2. Related Art Statement
Japanese Patent Application laid open for public inspection under Publication No. 7(1995)-9381 discloses a plurality of electric-component ("EC") supplying units each of which stores a plurality of electric components ("ECs") each as an element of an electric circuit (e.g., an electronic circuit) and is moved to supply the ECs to an object device such as an EC mounting device. The plurality of EC supplying units are supported on a support table such that respective EC-supply portions of the units are arranged along a straight line and, when the support table is moved by a table moving device, the respective EC-supply portions of the units are sequentially positioned at an EC-supply position where each of the units supplies one or more ECs to the object device. In each unit, the ECs are fed one by one to the EC-supply portion. A drive device which includes a drive member is provided in the vicinity of the EC-supply device. The drive device operates the drive member to drive a driven member of each unit being positioned at the EC-supply position, so that the ECs are fed one by one to the EC-supply portion. Each of the units disclosed in the above-identified application includes an EC feeding device which performs an EC feeding action and an EC-feeding preparing action while the support table is not moved by the table moving device, i.e., the each unit is stopped.
In the art of supplying ECs, it has been required to shorten an EC-supply cycle time, that is, a time period that is needed for the EC-supply portion of each unit to reach the EC-supply position and supply one EC to the object device, after its preceding unit supplies one EC to the object device. For example, in the case where the object device is the EC mounting device, it has been required, for the purpose of improving the efficiency of mounting of ECs, to shorten an EC-mount cycle time, that is, a time period that is needed for each EC to be mounted on a printed circuit board ("PCB") as a sort of circuit substrate, after its preceding EC is mounted on the PCB. To this end, it is required to shorten a time period that is needed for the EC mounting device to pick up the each EC from the EC-supply portion of each unit.
However, each of the conventional EC supplying units performs both the EC feeding action and the EC-feeding preparing action while the each unit is stopped. Therefore, shortening the EC-supply cycle time needs at least one of shortening a time period needed for the table moving device to move the support table, or shortening a time period needed for the EC feeding device to feed each EC. The former time period may be shortened by increasing the acceleration and/or deceleration of moving of the support table, and the latter time period may be shortened by increasing the acceleration and/or deceleration of feeding of each EC. However, if the acceleration and/or deceleration are/is increased in each case, a great vibration is produced when the moving of the table or the feeding of each EC is started or stopped. This leads to lowering the accuracy or reliability of supplying of each EC. That is, the great vibration may lower the accuracy of positioning of the EC-supply portion of each unit relative to an EC holder of the EC mounting device that picks up each EC from the each unit, may change the attitude of each EC being positioned at the EC-supply portion in each unit, or may cause each EC from jumping out of each unit. In each case, each unit may fail to supply each EC to the EC holder of the EC mounting device.